When the TV screen is black, when measuring the voltage with the voltage range of the multimeter, sometimes it can be restored to normal by touching it?

In that case, look at the picture tube for TV!

If it's a Hua Fei pipe, which is what we call a Philips pipe, it doesn't need to be repaired. I think the picture tube is broken. Hua Fei electron tube is used in Changhong's 29D85 TV and other models. When the TV screen is black, the acceleration can be adjusted to normal, and it will be restored when it is turned off and turned on again. Sometimes there will be a faint trace line on the screen, and it will return to normal when it touches the three primary colors. When it is used, it will flash from time to time and turn off automatically. This is the fault of the picture tube.

Tv sets of TCL, Konka and other manufacturers can directly declare that the picture tube is broken if the color is abnormal or the components on the video amplifier are burned.

And if you don't use Hua Fei tube, then you should focus on checking the black level delay circuit.

In addition, when you ask for help, you'd better find out the model and circuit of the TV set so that we can help you analyze the fault.